Dramatists who act in their own plays form one of the smallest Venn diagram overlaps in theatre – among the few included are Noël Coward, Harold Pinter, Dario Fo and Alan Bennett – but the subset has recently added two new members.

The actor Oliver Cotton is currently co-starring in his own play Daytona, while Nick Payne, a young playwright with no previous acting experience, has just completed a sell-out run at the small upstairs auditorium of the Royal Court theatre in London of The Art of Dying, his monologue about attitudes to death.

In choosing to say on the stage what they have put on the page, Cotton and Payne are reviving an older theatrical tradition – the actor-writer, whose progenitors include William Shakespeare and Ben Jonson – in contrast to a more recent trend for dual-skilled practitioners to keep the disciplines in separate rooms.

No previous experience … Nick Payne in The Art of Dying. Photograph: Tristram Kenton for the Guardian

Maxine Peake, who has just made her stage-writing debut with the cycling bio-drama Beryl at the West Yorkshire Playhouse, is not part of the cast. And the same division of labour was operated by two other recent candidates for joint membership of Equity and the Writers' Guild: Simon Paisley Day with his sex comedy Raving and Rory Kinnear, whose The Herd was on the stage of the Bush theatre in London while he was away filming a screen role.

The history of actor-writers who get entries in both the cast and creative sections of the programme suggests a possible risk and a potential benefit of having the author on double time; and each of these wisdoms is confirmed by one of the latest pair of author-performers.

The concern raised by this genre is that actor-dramatists instinctively create a performer's idea of a dream role: full of speeches that continue flashily for several pages. This fear results from the fact that two of the frontline dramatists with a performing past, John Osborne and Noël Coward, both wrote texts – Osborne's Look Back in Anger and Inadmissible Evidence and Coward's Present Laughter – that broadly take the form of monologues for a protagonist who is occasionally interrupted by someone else, although Osborne, unlike Coward, preferred someone else to play the parts.

In that respect, Oliver Cotton has the courage of Coward. Rather confirming the suspicion that an actor who writes a play may subconsciously settle a few scores with the ensemble pieces he has been in, the first act of Daytona essentially consists of an elderly American unloading about 40 minutes of almost unbroken backstory to the brother he hasn't seen for 30 years. As it happens, Cotton is cast as the speaker, with Harry Shearer as the listener.

It's true that, democratically, in the second act, Cotton sits back on a sofa and hands over the stage for 20 minutes or so to the impeccable Maureen Lipman as his sister-in-law, but the construction of Daytona seems to betray a regret in the dramatist – perhaps less likely to be the outcome of a survey of theatregoers – that nobody is writing really big set-piece speeches these days.

If the director Peter Hall was right to say that the tone of a playwright's work is almost always an extension of their speaking voice, then backstage conversations between the cast of Daytona may be somewhat one-sided. But, extending Hall's insight, dramatists delivering their own dialogue can give critics and audiences a useful clue to the personality behind the work and how the writer heard the lines in his head.

Pinter, for example, always tended to act his texts faster and lighter than most full-time actors would choose to do, as if to correct the reverential solemnity that sometimes attended his later plays. In other examples, it's true, awareness of the patron's choices paralysed later owners of the role: too many actors in the plays of Coward or Bennett have echoed, deliberately or accidental, the respectful plaintive lilt and lordly drawl of the author's own performances or recordings.

However, in The Art of Dying, seeing Nick Payne on stage offers a fascinating insight into the voice and mind behind such fine plays as If There Is I Haven't Found it Yet, Incognito and Constellations. Admittedly, the work's form could invite allegations of the sort of Coward- or Cotton-like spotlight hogging. Whereas Daytona allows two other actors on stage, Payne's play is a monologue, intertwining death-connected anecdotes about his father, the physicist Richard P Feynman, and a terminally ill person from Milton Keynes.

The whole show, though, is over in 45 minutes and Payne's performing persona – bashful, quizzical, switching between serious data – illuminates the sensibility and interests that make his plays so original and compelling.

It is also impossible not to admire his guts in taking on such a role with no training or experience, although, to my surprise, reports from the dressing room are that, later in the run, Payne's fear was less terror than boredom: he was surprised by how familiar the lines became and, in common with many dramatists who try acting, now has an enhanced respect for the way in which professional actors sustain energy and even discovery at the back end of a contract.

For that reason alone, there seems little chance of Payne turning up as an actor in one of his future plays, and with rare exceptions – of which Pinter is the greatest – author-performers are best advised to stay in the study or stalls for their own stuff. Next time, Oliver Cotton should follow the example of Peake, Paisley, Day and Kinnear and draw a line between the two sides of the CV.